Wyoming House Bill HB 68, with an effective date of January 1, 2017, would end Daylight Saving Time in the state after 2016. This bill has sponsors from the House and Senate. See the Time Zone Report Wyoming 2016 status page for more information and ongoing status.
According to information obtained from the Wyoming Legislature web site, the state had similar bills in 2001, 2005, and 2007.
Two neighboring states also currently have DST legislation. South Dakota has an ill-fated bill to adopt Year-Round Daylight Saving Time, which is not permitted by federal statutes. Utah has a bill similar to Wyoming’s which would end DST in it’s state, but the Utah bill does not specify an effective date.